U.S. patent number 7,246,438 [Application Number 11/006,704] was granted by the patent office on 2007-07-24 for method for producing a heat exchanger with a louvered fin.
This patent grant is currently assigned to Calsonic Kansei Corporation. Invention is credited to Kimio Nozaki, Kenji Tochigi.
United States Patent |
7,246,438 |
Nozaki , et al. |
July 24, 2007 |
Method for producing a heat exchanger with a louvered fin
Abstract
A method for producing a heat exchanger. A louvered fin is
provided, where the louvered fin has a first bridge member for
attaching a first corrugated strip and a straightening member of
the louvered fin together. A first corrugated strip is fixed
between first and second adjacent tubes of the heat exchanger such
that the first corrugated strip is kept in a straight shape by the
first and second tubes. The straightening member is detached from
the first corrugated strip by breaking the first bridge member such
that there is provided a first sandwiched structure having the
first corrugated strip fixed between the first and second
tubes.
Inventors: |
Nozaki; Kimio (Kanagawa,
JP), Tochigi; Kenji (Kanagawa, JP) |
Assignee: |
Calsonic Kansei Corporation
(Tokyo, JP)
|
Family
ID: |
18889617 |
Appl.
No.: |
11/006,704 |
Filed: |
December 8, 2004 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20050097746 A1 |
May 12, 2005 |
|
Related U.S. Patent Documents
|
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
10060083 |
Jan 31, 2002 |
|
|
|
|
Foreign Application Priority Data
|
|
|
|
|
Jan 31, 2001 [JP] |
|
|
2001-024481 |
|
Current U.S.
Class: |
29/890.047;
29/890.03 |
Current CPC
Class: |
B21D
53/085 (20130101); F28D 1/0435 (20130101); F28F
1/128 (20130101); F28F 2215/02 (20130101); Y10T
29/4938 (20150115); Y10T 29/4935 (20150115); Y10T
29/49366 (20150115) |
Current International
Class: |
B21D
53/06 (20060101); B21D 53/02 (20060101) |
Field of
Search: |
;29/890.047,890.03,890.07,412-415,417
;165/43,140,135,173,149,144,176 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
100 03 104 |
|
Aug 2000 |
|
DE |
|
0 431 917 |
|
Jun 1991 |
|
EP |
|
1 164 345 |
|
Dec 2001 |
|
EP |
|
1 301 666 |
|
Jan 1973 |
|
GB |
|
6-109390 |
|
Apr 1994 |
|
JP |
|
11-147149 |
|
Jun 1999 |
|
JP |
|
Primary Examiner: Hong; John C.
Attorney, Agent or Firm: Foley & Lardner LLP
Parent Case Text
The present application is a divisional of U.S. application Ser.
No. 10/060,083,filed Jan 31, 2002, now abandoned, the entire
contents of which are incorporated herein by reference.
Claims
What is claimed is:
1. A method for producing a heat exchanger, said method comprising
the steps of: (1) providing a louvered fin, said louvered fin
comprising: (a) a first corrugated strip having planar and
connecting portions that are alternately arranged to make a
corrugation, said first corrugated strip extending straight in a
longitudinal direction; (b) a plurality of first louvers formed in
each planar portion such that said first louvers are arranged in a
lateral direction perpendicular to said longitudinal direction,
said first louvers in each planar portion being configured to be in
asymmetry with respect to a center line of the planar portion in
said lateral direction; (c) a straightening member for keeping said
first corrugated strip in a straight shape in said longitudinal
direction, said straightening member extending along a longitudinal
side of said first corrugated strip; and (d) a first bridge member
for attaching said first corrugated strip and said straightening
member together, (2) fixing said first corrugated strip between
first and second adjacent tubes of said heat exchanger such that
said first corrugated strip is kept in said straight shape by said
first and second tubes; and (3) detaching said straightening member
from said first corrugated strip by breaking said first bridge
member such that there is provided a first sandwiched structure
having said first corrugated strip fixed between said first and
second tubes.
2. A method according to claim 1, wherein said louvered fin is
prepared by a method comprising the steps of: (4) providing a first
blank of said first corrugated strip with said straightening member
and said first bridge member such that said straightening member
extends along a longitudinal side of said first blank and is
attached to said first blank through said first bridge member; (5)
forming said first louvers in said first blank; (6) shaping said
first blank into a first corrugated blank; and (7) cutting each of
said first corrugated blank and said straightening member to have a
length in said longitudinal direction, thereby preparing said
louvered fin.
3. A method according to claim 2, wherein, in the step (5), said
first louvers are orientated in a first uniform direction.
4. A method according to claim 1, wherein said straightening member
comprises: a second corrugated strip extending along said
longitudinal side of said first corrugated strip and having planar
and connecting portions that are alternately arranged to make a
corrugation; and a plurality of second louvers formed in each
planar portion of said second corrugated strip such that said
second louvers are arranged in said lateral direction and are
symmetrical to said first louvers about said first bridge
member.
5. A method according to claim 4, wherein said louvered fin is
prepared by a method comprising the steps of: (4) providing a first
blank of said first corrugated strip with a second blank of said
second corrugated strip and the first bridge member such that said
second blank extends along a longitudinal side of said first blank
and is attached to said first blank through said first bridge
member; (5) forming said first and second louvers respectively in
said first and second blanks; (6) shaping said first and second
blanks respectively into first and second corrugated blanks; and
(7) cutting each of said first and second corrugated blanks to have
a length in said longitudinal direction, thereby preparing said
louvered fin.
6. A method according to claim 5, wherein the step (4) is conducted
by perforating a blank of said louvered fin at regular intervals in
a longitudinal direction of said blank such that said first and
second blanks are formed and such that said first bridge member is
provided between adjacent first and second perforations formed by
said perforating.
7. A method according to claim 6, wherein the step (6) is conducted
by bending said first and second blanks at a position of said first
bridge member in said lateral direction.
8. A method according to claim 5, further comprising the sequential
steps of: (8) fixing said second corrugated strip between third and
fourth tubes to prepare a second sandwiched structure; (9) rotating
said first sandwiched structure, which has said first corrugated
strip fixed between said first and second tubes, and said second
sandwiched structure relative to each other by about 90 degrees to
break said first bridge member; (10) attaching first and second
tanks to said first and second tubes; and (11) attaching third and
fourth tanks to said third and fourth tubes.
9. A method for producing a heat exchanger, said method comprising
the steps of: (1) providing a louvered fin, said louvered fin
comprising: (a) a first corrugated strip having planar and
connecting portions that are alternately arranged to make a
corrugation, said first corrugated strip extending straight in a
longitudinal direction; (b) a plurality of first louvers formed in
each planar portion such that said first louvers are arranged in a
lateral direction perpendicular to said longitudinal direction,
said first louvers in each planar portion being configured to be in
asymmetry with respect to a center line of the planar portion in
said lateral direction; (c) a straightening member for keeping said
first corrugated strip in a straight shape in said longitudinal
direction, said straightening member extending along a longitudinal
side of said first corrugated strip; and (d) a first bridge member
for attaching said first corrugated strip and said straightening
member together, (2) fixing said first corrugated strip between
first and second adjacent tubes of said heat exchanger such that
said first corrugated strip is kept in said straight shape by said
first and second tubes; and (3) detaching said straightening member
from said first corrugated strip by breaking said first bridge
member such that there is provided a first sandwiched structure
having said first corrugated strip fixed between said first and
second tubes. wherein said straightening member comprises: a second
corrugated strip extending along said longitudinal side of said
first corrugated strip and having planar and connecting portions
that are alternately arranged to make a corrugation; and blanks; a
plurality of second louvers formed in each planar portion of said
second corrugated strip such that said second louvers are arranged
in said lateral direction and are symmetrical to said first louvers
about said first bridge member, wherein said louvered fin is
prepared by a method comprising the steps of: (4) providing a first
blank of said first corrugated strip with a second blank of said
second corrugated strip and the first bridge member such that said
second blank extends along a longitudinal side of said first blank
and is attached to said first blank through said first bridge
member; (5) forming said first and second louvers respectively in
said first and second (6) shaping said first and second blanks
respectively into first and second corrugated blanks; and (7)
cutting each of said first and second corrugated blanks to have a
length in said longitudinal direction, thereby preparing said
louvered fin, wherein each connecting portion of said first and
second corrugated strips is prepared by straightening a V-shaped
portion of each of said first and second blanks into a planar
shape.
10. A method for producing a heat exchanger, said method comprising
the steps of: (1) providing a louvered fin, said louvered fin
comprising: (a) a first corrugated strip having planar and
connecting portions that are alternately arranged to make a
corrugation, said first corrugated strip extending straight in a
longitudinal direction; (b) a plurality of first louvers formed in
each planar portion such that said first louvers are arranged in a
lateral direction perpendicular to said longitudinal direction,
said first louvers in each planar portion being configured to be in
asymmetry with respect to a center line of the planar portion in
said lateral direction; (c) a straightening member for keeping said
first corrugated strip in a straight shape in said longitudinal
direction, said straightening member extending along a longitudinal
side of said first corrugated strip; and (d) a first bridge member
for attaching said first corrugated strip and said straightening
member together, (2) fixing said first corrugated strip between
first and second adjacent tubes of said heat exchanger such that
said first corrugated strip is kept in said straight shape by said
first and second tubes; and (3) detaching said straightening member
from said first corrugated strip by breaking said first bridge
member such that there is provided a first sandwiched structure
having said first corrugated strip fixed between said first and
second tubes, wherein the step (3) is conducted by applying a
vibration to said louvered fin to break said first bridge
member.
11. A method for producing a heat exchanger, said method comprising
the steps of: (1) providing a louvered fin, said louvered fin
comprising: (a) a first corrugated strip having planar and
connecting portions that are alternately arranged to make a
corrugation, said first corrugated strip extending straight in a
longitudinal direction; (b) a plurality of first louvers formed in
each planar portion such that said first louvers are arranged in a
lateral direction perpendicular to said longitudinal direction,
said first louvers in each planar portion being configured to be in
asymmetry with respect to a center line of the planar portion in
said lateral direction; (c) a straightening member for keeping said
first corrugated strip in a straight shape in said longitudinal
direction, said straightening member extending along a longitudinal
side of said first corrugated strip; and (d) a first bridge member
for attaching said first corrugated strip and said straightening
member together, (2) fixing said first corrugated strip between
first and second adjacent tubes of said heat exchanger such that
said first corrugated strip is kept in said straight shape by said
first and second tubes; and (3) detaching said straightening member
from said first corrugated strip by breaking said first bridge
member such that there is provided a first sandwiched structure
having said first corrugated strip fixed between said first and
second tubes. wherein the step (3) is conducted by rotating said
first sandwiched structure and said straightening member relative
to each other to break said first bridge member.
Description
BACKGROUND OF THE INVENTION
The present invention relates to a vehicular heat exchanger,
particularly to a louvered fin for a heat exchanger, which has (a)
a corrugated strip having planar and connecting portions that are
alternately arranged to make a corrugation and (b) a plurality of
louvers formed in each planar portion such that the louvers are
arranged in a lateral direction, to a heat exchanger having such
louvered fin, and to a method for producing such heat
exchanger.
In an automotive water-cooled engine, a heat exchanger such as
radiator is disposed at a front position in an engine room, and
this radiator serves to cool an engine cooling water. As generally
known, this radiator has a pair of tanks (headers), a plurality of
tubes extending between the tanks, and a plurality of fins each
being disposed between two adjacent tubes. At the position of each
fin, a heat exchange is conducted between air flowing through the
fins and the cooling water passing through the tube.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a louvered fin
for a heat exchanger, which louvered fin is prevented from curling
in the production of the heat exchanger, even if louvers of the
louvered fin are in asymmetry in its lateral direction.
It is another object of the present invention to provide a heat
exchanger produced by using such louvered fin.
It is still another object of the present invention to provide a
method for producing such heat exchanger.
According to the present invention, there is provided a louvered
fin for a heat exchanger. This louvered fin comprises:
a first corrugated strip having planar and connecting portions that
are alternately arranged to make a corrugation, the first
corrugated strip extending straight in a longitudinal
direction;
a plurality of first louvers formed in each planar portion such
that the first louvers are arranged in a lateral direction
perpendicular to the longitudinal direction, the first louvers in
each planar portion being configured to be in asymmetry in the
lateral direction;
a straightening member for keeping the first corrugated strip in a
straight shape in the longitudinal direction, the straightening
member extending along a longitudinal side of the first corrugated
strip; and
a first bridge member for attaching the first corrugated strip and
the straightening member together such that a detachment of the
straightening member from the first corrugated strip is allowed by
breaking the first bridge member after the first corrugated strip
is fixed between first and second adjacent tubes of the heat
exchanger in a production of the heat exchanger.
According to the present invention, there is provided a heat
exchanger comprising a first assembly. The first assembly
includes:
first and second tanks;
first and second tubes extending between the first and second tanks
such that a heat-exchanger medium is allowed to flow from the first
tank to the second tank;
the first corrugated strip fixed between the first and second
tubes, the first corrugated strip having a fracture surface at a
longitudinal side of the first corrugated strip; and
the first louvers. This heat exchanger is produced by a method
comprising the steps of:
(1) providing a louvered fin comprising (a) the first corrugated
strip; (b) the first louvers; (c) a straightening member for
keeping the first corrugated strip in a straight shape in the
longitudinal direction, the straightening member extending along a
longitudinal side of the first corrugated strip; and (d) a first
bridge member for attaching the first corrugated strip and the
straightening member together;
(2) fixing the first corrugated strip between the first and second
tubes such that the first corrugated strip is kept in the straight
shape by the first and second tubes; and
(3) detaching the straightening member from the first corrugated
strip by breaking the first bridge member such that there is
provided a sandwiched structure having the first corrugated strip
fixed between the first and second tubes and such that the fracture
surface of the first corrugated strip is exposed.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view showing a louvered fin according to an
embodiment of the present invention;
FIGS. 2-4 are perspective views showing sequential steps for
producing a heat exchanger in accordance with an embodiment of the
present invention;
FIG. 5 is an end view showing a radiator tube according to an
embodiment of the present invention;
FIG. 6 is a sectional view taken along the lines B-B in FIG. 1;
FIG. 7 is a schematic view showing steps for producing the louvered
fin;
FIG. 8 is a plan view showing a blank of the louvered fin;
FIG. 9 is a perspective view showing a first corrugated strip
having a fracture surface formed by detaching a straightening
member from the first corrugated strip;
FIG. 10 is a plan view showing another blank of the louvered
fin;
FIGS. 11(a) and 11(b) are side views showing sequential steps for
forming a corrugated blank of the louvered fin in accordance with
another embodiment of the present invention;
FIG. 12 is a partial perspective view showing a louvered fin not
according to the present invention;
FIG. 13 is a perspective view showing a condition of curling of the
louvered fin of FIG. 12; and
FIG. 14 is a laterally sectional view of the louvered fin of FIG.
12.
DETAILED DESCRIPTION
FIG. 12 shows a louvered fin 1 not according to the present
invention. This louvered fin 1 is made of a thin strip 2 and has
corner portions 1a and planar portions 1b that are alternately
continuously arranged to make a corrugation. Each planar portion 1b
has a plurality of louvers 3 that are arranged in the lateral
direction and are orientated obliquely relative to the base flat
wall of the planar portion 1b.
In case that all the louvers 3 in each planar portion 1b are
orientated in a uniform direction, the louvered fin 1 becomes
imbalanced in the lateral direction. With this, the louvered fin 1
tends to curl, as shown in FIG. 13. This makes impossible to
conduct an automated assembly of this louvered fin 1 for producing
a heat exchanger. In order to prevent this curling, there is a
proposal in which the left half and right half louvers 3a and 3b
are orientated in opposite directions to make a symmetrical
configuration about a center line C of each planar portion 1b, as
shown in FIG. 14. This proposal makes it possible to maintain the
louvered fin 1 in a straight shape in its longitudinal
direction.
However, according to the above proposal, air flows from a first
side F1 of the planar portion 1b to a second side F2 through the
louvers 3a, as shown by the arrow of two-dot chain line in FIG. 14.
Then, air flows from the second side F2 to the first side F1
through the louvers 3b due to the orientation of the louvers 3b.
Therefore, air flows through the louvered fin 1 in a meandering
manner. This increases air flow resistance and thereby lowers heat
exchange efficiency.
The present invention was made in view of such problem. The present
invention makes it possible to prevent curling of a louvered fin of
a heat exchanger in the production of the heat exchanger, even if
its louvers are in asymmetry in the lateral direction, and thereby
makes it possible to conduct an automated assembly of louvered fin
for producing a heat exchanger.
As stated above, the louvered fin according to the present
invention has the straightening member extending along a
longitudinal side of the first corrugated strip. This straightening
member is capable of preventing the above-mentioned curling of a
louvered fin during the production of a heat exchanger, even if the
first louvers in each planar portion are configured to be in
asymmetry in the lateral direction and even if planar portions each
having such asymmetrical louvers are continuously formed in the
longitudinal direction of the louvered fin. Therefore, when the
first corrugated strip is disposed or fixed between first and
second tubes of a heat exchanger, it is possible to maintain the
first corrugated strip in a straight shape. Therefore, it becomes
possible to easily and precisely conduct an assembly of the
louvered fin. It is possible to detach the straightening member
from the first corrugated strip by breaking the first bridge member
after the first corrugated strip is fixed between the first and
second tubes. By this breaking, the first corrugated strip has a
fracture surface only at one longitudinal side of the first
corrugated strip. The other longitudinal side does not have such
fracture surface. Therefore, the existence of this fracture surface
makes it easy to recognize the proper orientation of the louvered
fin and thereby to conduct the proper assembly of the louvered fin.
For example, it is possible to easily recognize one longitudinal
side (having the fracture surface) as the front or rear side in the
production of a heat exchanger. This improves the assembly
workability of a heat exchanger.
With reference to FIGS. 1-10, 11(a) and 11(b), exemplary
embodiments according to the present invention will be described in
detail in the following. FIG. 1 shows a louvered fin according to
an embodiment of the present invention. This louvered fin has a
first corrugated strip 23 and a second corrugated strip 33. The
second corrugated strip 33 is capable of serving as the
straightening member for keeping the first corrugated strip 23 in a
straight shape in the longitudinal direction of the first
corrugated strip 23. As shown in FIGS. 2-4, the first and second
corrugated strips 23 and 33 are respectively simultaneously used
for producing first and second radiators (first and second
assemblies) 20 and 30. As will be explained hereinafter, a first
sandwiched structure having the first corrugated strip 23 fixed
between first and second adjacent tubes 22, 22 is detached from a
second sandwiched structure having the second corrugated strip 33
fixed between third and fourth adjacent tubes 32, 32 for
simultaneously producing the first and second radiators 20 and
30.
As shown in FIG. 4, the first radiator 20 has first and second
tanks (headers) 21 and 21a and a plurality of tubes 22 extending
between the first and second tanks 21 and 21a such that a
heat-exchanger medium (cooling water) is allowed to flow from one
of the first and second tanks 21 and 21a to the other tank. The
first radiator 20 further has the first corrugated strip 23 that is
fixed between first and second adjacent tubes 22, 22 by brazing. In
other words, the first and second tanks 21 and 21a are attached to
the above-mentioned first sandwiched structure for producing the
first radiator 20. Furthermore, the first sandwiched structure is
reinforced at its both sides with a pair of reinforcements 24 and
24a. The second radiator 30 has a construction substantially
identical with that of the first radiator 20. Thus, it is possible
by the present invention to easily simultaneously produce a pair of
identical radiators. The second radiator 30 has third and fourth
tanks (headers) 31 and 31a and a plurality of tubes 32 extending
between the third and fourth tanks 31 and 31a such that a
heat-exchanger medium (cooling water) is allowed to flow from one
of the third and fourth tanks 31 and 31a to the other tank. The
second radiator 30 further has the second corrugated strip 33 that
is fixed between third and fourth adjacent tubes 32 by brazing. In
other words, the third and fourth tanks 31 and 31a are attached to
the above-mentioned second sandwiched structure for producing the
second radiator 30. Furthermore, the second sandwiched structure is
reinforced at its both sides with a pair of reinforcements 34 and
34a.
As shown in FIG. 5, each tube 22 or 32 has a compressed
configuration having opposite sides parallel with each other. Each
tube is inserted at its both ends to insertion holes (not shown in
the drawings) of the tanks and is fixed to the tanks by brazing.
Upon this, each reinforce is also fixed at its both ends to the
tanks by brazing. While a heat-exchanger medium flows through each
tube, heat of this medium is transmitted to the first or second
corrugated strip 23 or 33 and then to the air flowing therethrough,
thereby conducing a heat exchange with the air and cooling of the
heat-exchanger medium.
As shown in FIG. 1, the louvered fin has at its center in the
longitudinal direction a perforated portion 40 at a boundary
between the first and second corrugated strips 23 and 33. The
perforated portion 40 has a plurality of bridge members 40a each
being defined between adjacent slits 40b in the longitudinal
direction. These bridge members 40a are broken for detaching the
first and second corrugated strips 23 and 33 from each other, after
each corrugated strip 23 or 33 is fixed between corresponding two
adjacent tubes. This makes it possible to prevent curling of each
corrugated strip 23 or 33.
Each of the first and second corrugated strips 23 and 33 is a thin
strip made of aluminum and has planar portions 23b or 33b and
connecting portions (bent portions) 23a or 33a that are alternately
continuously arranged to make a corrugation. Furthermore, as shown
in FIGS. 1 and 6, first louvers 25 are formed in each planar
portion 23b such that the first louvers 25 in each planar portion
23b are arranged in the lateral direction of the first corrugated
strip 23 and are configured to be in asymmetry in the lateral
direction. In other words, the first louvers 25 in each planar
portion 23b are orientated obliquely in a first uniform direction
relative to the base wall of the planar portion 23b. That is, the
first louvers 25 have their openings 25a that are orientated
obliquely relative to the base wall of the planar portion 23b.
Thus, the first louvers 25 in each planar portion 23b are
asymmetrical in the lateral direction about the center line C1 of
the planar portion 23b.
Similarly, second louvers 35 are formed in each planar portion 33b
such that the second louvers 35 in each planar portion 33b are
arranged in the lateral direction of the first corrugated strip 23
and are configured to be in asymmetry in the lateral direction. In
other words, the second louvers 35 in each planar portion 33b are
orientated obliquely in a second uniform direction relative to the
base wall of the planar portion 33b. That is, the second louvers 35
have their openings 35a that are orientated obliquely relative to
the base wall of the planar portion 33b. Thus, the second louvers
35 in each planar portion 33b are asymmetrical in the lateral
direction about the center line C2 of the planar portion 33b. In
contrast, the first and second louvers 25 and 35 are symmetrical to
each other about the perforated portion 40. Each of the first and
second louvers 25 and 35 is formed by cutting the base wall of the
planar portion 23b or 33b and by raising a predetermined portion of
the base wall.
With reference to FIG. 7, a method for producing the louvered fin
will be explained in detail in the following. At first, a blank 51
(in the form of thin strip or ribbon) of the louvered fin is taken
from a roll 50. Then, the blank 51 is perforated by passing the
blank 51 between a pair of perforation forming rollers 52, thereby
perforating the blank 51 at regular intervals in a longitudinal
direction of the blank 51. With this, there are provided a first
blank of the first corrugated strip 23, a second blank of the
second corrugated strip 33, and bridge members 40a each being
provided between adjacent first and second perforations (slits)
(see FIG. 8). After the perforation step, the blank 51 is passed
between a pair of corrugation forming rollers 53. With this, the
first and second louvers 25 and 35 are formed, and at the same time
the blank 51 is shaped into a corrugated blank by bending the blank
51 at a position of each bridge member 40a in the lateral
direction. The corrugation forming rollers 53 have a plurality of
star-like gears (not shown in the drawings) that are meshed with
each other by turning the corrugation forming rollers 53, for
making a corrugation. Each star-like gear is formed with teeth for
forming the first and second louvers 25 and 35. When the blank 51
is passed between the corrugation forming rollers 53, predetermined
portions of the base wall of each planar portion 23b or 33b are cut
and raised by the teeth of each star-like gear, thereby forming the
first and second louvers 25 and 35.
When the corrugated blank is then passed between a pair of pitch
adjusting rollers 54, the pitch of the corrugated blank (i.e., the
distance between adjacent connecting portions 23a or 33a) is
adjusted under a condition that the corrugated blank is compressed
in the longitudinal direction. After that, the corrugated blank is
cut to have a predetermined length. With this, the resulting
louvered fin shown in FIG. 1 is formed with the first and second
corrugated strips 23 and 33 attached with each other by the bridge
members 40a.
As shown in FIG. 6, the first and second louvers 25 and 35 are
respectively orientated in the first and second directions that are
opposite to each other. In other words, the openings of the first
louvers 25 are symmetrical to those of the second louvers 35 about
the perforated portion 40.
As shown in FIG. 8, the perforated portion 40 has bridge members
40a each defined by adjacent slits 40b. The bridge members 40a are
formed at positions of connecting portions 23a and 33a at regular
intervals (at every 8 connecting portions 23a and 33a in FIG. 1).
The slit 40b may have a certain width (see FIGS. 1 and 8) or no
width (not shown in the drawings) in the lateral direction. In the
latter case, the slit 40b is a cut having no width. In this case,
it is possible to get rid of wastes generated by preparing the
slits of a certain width.
With reference to FIGS. 2-4, a method for producing a heat
exchanger using the louvered fin will be explained in detail in the
following. A first sandwiched structure is prepared by alternately
disposing the first corrugated strips 23 and the tubes 22 and by
putting reinforces 24 and 24a at both ends. As shown in FIG. 3, the
first corrugated strip 23 at the top position is disposed between
the reinforce 24 and the tube 22. Similarly, that at the bottom
position is disposed between the reinforce 24a and the tube 22. The
other first corrugated strips 23 are each disposed between
corresponding two adjacent tubes 22. During the production of the
first sandwiched structure, a second sandwiched structure is also
prepared by substantially the same manner, thereby preparing an
integral body of the first and second sandwiched structures. The
first and second sandwiched structures, which are attached with
each other through the bridge members 40a, are pre-assemblies of
the first and second radiators 20 and 30. In the preparation of
this integral body, all of the louvered fins are properly
orientated such that all of the first louvers 25 of all the first
corrugated fins 23 are orientated in a first uniform direction and
such that all of the second louvers 35 of all the second corrugated
fins 33 are orientated in a second uniform direction that is
opposite to the first uniform direction (see FIG. 6).
Then, the first and second sandwiched structures are detached from
each other by breaking the bridge members 40a under a condition
that upward and downward forces F are added to the first and second
sandwiched structures in order to press the first and second
corrugated strips 23 and 33 and the corresponding tubes 22 and 32
against each other. This detachment can be conducted by applying a
vibration shock in the longitudinal direction of the louvered fins
at a position corresponding to the bridge members 40a. By applying
this vibration shock (shearing force), the first and second
corrugated strips 23 and 33 are forced to move relative to each
other, thereby easily breaking the bridge members 40a. With this,
as shown in FIG. 9, each of the first and second corrugated strips
23 and 33 is formed at its one longitudinal side with fracture
surfaces 41 when the first and second sandwiched structures are
separated from each other.
After breaking the bridge members 40a, as shown in FIG. 4, the
first and second structures are rotated relative to each other by
about 90 degrees to make a cross-like shape. At this angular
position, the first and second tanks 21 and 21a are attached to the
first sandwiched structure, and the third and fourth tanks 31 and
31a are attached to the second sandwiched structure. In fact, the
former attachment is conducted by inserting end portions of the
tubes 22 and of the reinforces 24 and 24a into predetermined holes
of the first and second tanks 21 and 21a, followed by brazing.
Similarly, the latter attachment is conducted by inserting end
portions of the tubes 32 and of the reinforces 34 and 34a into
predetermined holes of the third and fourth tanks 31 and 31a,
followed by brazing. Since the attachment of the first to fourth
tanks is conducted at the above angular position, it is possible to
provide a relatively large space near end portions of the tubes 22
or 32 (see FIG. 4). Therefore, it is possible to easily conduct
this attachment without having intervention of the first or second
tank 21 or 21a in the attachment of the third or fourth tank 31 or
31a and vice versa. Furthermore, it is possible to conduct this
attachment in an assembly line with a small space.
As mentioned above, the first and second corrugated strips 23 are
put alongside of each other and attached with each other by the
bridge members 40a. The first and second louvers 25 and 35 of all
the first and second corrugated strips 23 and 33 are respectively
orientated in a first uniform direction and a second uniform
direction that is opposite to the first uniform direction.
Therefore, as shown in FIG. 10, as long as the first and second
corrugated strips 23 and 33 are attached with each other, the
second corrugated strip 33 prevents the first corrugated strip 23
from curling in one direction, and the first corrugated strip 23
prevents the second corrugated strip 33 from curling in the other
direction. In contrast with the present invention, if the first and
second corrugated strips 23 and 33 are detached from each other
under a condition that each of the first and second corrugated
strips 23 and 33 is not fixed between two adjacent tubes, the first
and second corrugated strips 23 and 33 tend to curl in one and the
other directions, respectively. However, according to an embodiment
of the present invention, the detachment is conducted under a
condition that each of the first and second corrugated strips 23
and 33 is fixed between two adjacent tubes. Therefore, it is
certainly possible to prevent curling of the first and second
corrugated strips 23 and 33 and thereby to keep these strips in the
straight form. This makes it possible to simultaneously conduct an
automated assembly of the first and second radiators.
As mentioned above, it is possible to break the bridge members 40a
by applying a vibration shock. Furthermore, this breaking can also
be conducted by rotating the first and second sandwiched structures
relative to each other by a predetermined angle in the longitudinal
direction of the louvered fin. In this case, a relative rotational
force acts as a shearing force on the bridge members 40a, thereby
easily breaking the bridge members 40a.
As shown in FIG. 8, each bridge member 40a between two adjacent
slits 40b has a relatively short width in the longitudinal
direction of the louvered fin. Therefore, it is easily possible to
break the bridge members 40a by applying shearing force. As is seen
from FIG. 1, each bridge member 40a is formed between the laterally
aligned connecting portions (bent portions) 23a and 33a of the
first and second corrugated strips 23 and 33. These connecting
portions 23a and 33a are greater than the planar portions 23b and
33b in rigidity. Therefore, it is possible to prevent deformation
of the first and second corrugated strips 23 and 33 caused by
applying a breaking load to the bridge members 40a, as compared
with a case in which each bridge member is formed between the
planar portions.
As mentioned above, it is possible to detach the first and second
corrugated strips 23 and 33 from each other by breaking the bridge
members 40a. By this breaking, each of the first and second
corrugated strips 23 and 33 has a fracture surface only at one
longitudinal side thereof. The other longitudinal side does not
have such fracture surface. Therefore, the existence of this
fracture surface makes it easy to recognize the proper orientation
of the louvered fin. This also makes it possible to easily
recognize the front or rear surface of the first and second
radiators 20 and 30, thereby improving the assembly efficiency of
these radiators.
As mentioned above, the openings 25a or 35a of the first or second
louvers 25 or 35 are orientated in a uniform direction. Therefore,
it is possible to prevent air from flowing in a meandering manner
through the first or second corrugated strips 23 or 33. This
provides a smooth air flow and increases the amount of air flowing
therethrough, thereby improving heat exchange efficiency.
FIGS. 11(a) and 11(b) show sequential steps for forming a
corrugated blank of the louvered fin in accordance with another
embodiment of the present invention. According to this embodiment,
a V-shaped portion (groove) 42 is formed at first at a position
corresponding to each connecting portion 23a or 33a of the first
and second corrugated strips 23 and 33 (see FIG. 11(a)). Then, each
V-shaped portion 42 is straightened into the connecting portion 23a
or 33a that is planar in shape (see FIG. 11(b)). This planar
connecting portion 23a or 33a is improved in preventing deformation
of the connecting portions when a breaking load acts on the bridge
members 40a. Furthermore, the planar connecting portions 23a or 33a
are capable of making the planar portions 23b or 33b longer in
effective length L (see FIG. 11(b)), as compared with the case of
arcuate connecting portions. Therefore, it is possible to make the
widths of the first and second corrugated strips 25 and 35 longer,
thereby making their opening areas greater. With this, it is
possible to increase the amount of air flowing therethrough and to
improve the heat exchange efficiency.
In the invention, the straightening member is not limited to the
second corrugated strip 35. For example, the straightening member
may be a ribbon having no louvers. In this case too, it is needless
to say that the straightening member is attached to the first
corrugated strip through the bridge member and is subjected to a
separation from the first corrugated strip in the production of a
heat exchanger, as described above.
The present invention is not limited to that the first or second
louvers 25 or 35 in each planar portion 23b or 33b are orientated
in a uniform direction (FIG. 6). For example, it is possible to
design the first or second louvers 25 or 35 in each planar portion
23b or 33b such that the total opening area of the left half
louvers in each planar portion 23b or 33b is different from that of
the right half louvers in each planar portion 23b or 33b. In this
case too, the first and/or second corrugated strips 23 and 33 tend
to have the above-mentioned curling. Therefore, the present
invention can be used in this case, too.
It is optional in the present invention to conduct a brazing
between the first or second corrugated strip 23 or 33 and two
adjacent tubes 22 or 32 and then to conduct a detachment of the
first and second corrugated strips 23 and 33 from each other.
It is needless to say that a heat exchanger according to the
present invention is not limited to the above-mentioned first and
second radiators 20 and 30. For example, the heat exchanger may be
a heater core or an evaporator in cooling cycle.
The entire disclosure of Japanese Patent Application No.
2001-024481 filed on Jan. 31, 2001, including specification,
drawings, claims and summary, is incorporated herein by reference
in its entirety.
* * * * *